Mercedes-Benz Ponton
Solex 32 PAITA Carburetor Rebuild

Jack Kotrba / kotrba@lkdllink.net



The kit I used to rebuild my carburetors is made by "Royze." It is called a carburetor tune up kit, and the P/N is SO-10K. It consists of; all the gaskets, the seals for the jets, the accelerator pump diaphragm, an idle mixture adjusting screw, and the needle and seat for fuel inlet. It did not have the bellows for the shock, or the diaphragm for the starter air valve. 

Note: The kit is available from Miller's Mercedes.  See: Links

View photos of a Solex Type 32 PAITA carburetor

View exploded parts diagram of Solex Type 32 PAITA carburetor

Disassembly

After removing the carburetor from your car, remove the four screws #196 that hold the top on, and remove the top #151 and top gasket #152. 

· Remove fuel inlet needle valve #156 and gasket #157 found on the under side of top (there has been different thickness gaskets used to adjust fuel level on these carburetors. The kit I used came with a thin and a thick gasket.

· On the top of the carburetor you will find the starter air valve. Remove the three screws that hold the starter air valve cover on, then remove the cover #166 with spring #169 and diaphragm #168. The tune up kit I used did not come with the diaphragm, so I reused the one I took out (until I find a new one).

· Next, remove the float #52 and pivot pin #53 from the float chamber. Remove the screw #83 for the accelerator pump injection tube, and remove injection tube #81 with gasket #82. Then remove the idle air jet #70 and air correction jets # 65a and 65b from the top of the carburetor body. There's 5 jets and 1 ball valve found on the outside of the carburetor. Remove them for cleaning. The parts are: Starter fuel jet with seal #71 and 72 Main jet plug with jet and seal (stage 1) #66, 67 and 68 Main jet with seal (stage 2) #68a and 68b Pump jet with seal #73 and 74 Idle fuel jet # 69 Ball valve with seal and screen #77, 78 and 79.

Remove the idle mixture adjusting screw with spring #27 and 26.

· Next remove the four screws #109 that attach the accelerator pump #91 to the base. Remove pump #91 with gasket #108. 

· Then remove the two screws # 102 that hold the pump together. Inside you will find; the plate valve #95, valve spring #96, pump diaphragm #93, and diaphragm spring # 94. The new diaphragm doesn't come with the shaft. 

· Remove the nut and washer from the diaphragm shaft, and replace the diaphragm. 

· Next, to remove starter rotary slide valve #131, remove the 2 screws #138 from the Bowden cable anchor plate #136, and then remove the 4 screws #132 holding the starter slide valve. 

· To remove and disassemble the shock absorber #38, first remove the cotter pin #48b and washer # 48a from the top of the shock, and the one screw #37c that holds it to the base. Remove the lower washer #48a and cotter pin # 48b. Remove the bellows #42 and unscrew the top of the shock and remove shaft. 

· Remove four screws #28 from the bottom of the carburetor, and remove nut and washer #57a and 57b from throttle valve shaft #54 and remove throttle butterfly section #1

· Next remove the four screws #28 that hold the throttle butterfly section to the float chamber and remove throttle butterfly section and insulation flange #31. There should be no need to disassemble the carburetor any further. Cleaning can be done with a can or two of spray carburetor cleaner. Clean all parts and passages, and blow them out with compressed air.

Then you know what they say, Reassemble in reverse order!

After reassemble you will need to adjust the fuel level and the fuel pump injection amount.

Reassemble

Make certain all jets and carburetor passages are clean. · Replace throttle butterfly section with insulation flange making sure surface is clean and smooth. Install new seals on jets # 66, 68a, 71, 73, and 77 and install (preferably in the same place they came out of). · Reassemble accelerator pump with new diaphragm and install with new gasket. 

· Install starter rotary slide valve and Bowden cable anchor plate. Install jets # 65a, 65b, and 70, and injection tube with new gasket. Install float with shaft. 

· Install new float needle valve with gasket, in top of carburetor and install top with new gasket. Install starter air valve. When reassembling the shock absorber fill it to the bottom of the filler plug hole with SAE 10W engine oil (approx. 1.2 cc). And install shock.

Adjusting Fuel Level

After installing carburetor, run your car for a few minutes at idle speed, shut off engine and remove carburetor top. Measure the distance between the top of the carburetor float chamber and the surface of fuel at the separating partition between float chamber and carburetor throat. Measurement should be between 19 and 21 mm. There is different thickness seals for the fuel inlet valve that will change the fuel level, a difference of ½ mm. Will change the fuel level 1 mm. Thinner seals will increase the fuel level. You can also bend the float to adjust the fuel level, holding float arm and bending float up will increase fuel level.

Measurement of injection amount

This should be done at the same time that you check the fuel level, with the carburetor cover removed. You well need a fuel injection tube that has been bent, and then from a closed throttle position, open the throttle completely, catching the fuel in a container and measuring the amount that was discharged. The amount should be 1.1 to 1.3 cm3/ stroke. To increase the amount of discharge increase the stroke of the accelerator pump by screwing in the nut on the connecting rod. To decrease it turn the nut out. I have a bent injection tube for this purpose for anyone to use.

I will gladly try to answer anyone's email questions. Contact me at: kotrba@lkdllink.net

Jack Kotrba
Annandale, Minnesota
1959 W180 220 sedan "Hoxter"
1959 W180 220S coupé
1979 W116 280SE sedan
MBCA Twin Cities Section
My Mercedes Page: www.angelfire.com/mn/jacksbenz


Created: May 1998 / Last Update: October 15, 2013
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